Electromagnetic latch trip switch



Sept. 26, 1950 M. L. JEFFREY ELECTROMAGNETIC LATCH TRIP SWITCH ll Sheets-Sheet 1 Filed Dec. 31, 1945 ATTORNEY Sept. 26, 1950 M. L. JEFFREY ELECTROMAGNETIC LATCH TRIP SWITCH ll Sheets-Sheet 2 Filed Dec. 31, 1945 H m m T A Sept. 26, 1950 v L JEFFREY 2,523,370

ELECTROMAGNETIC LATCH TRIP SWITCH ,4 TTaQNEY Sept. 26, 1950 M. 1.. JEFFREY 2,523,370

ELECTROMAGNETIC LATCH TRIP SWITCH Filed Dec. 31, 1945 ll Sheets-Sheet 5 8 INVENTOR.

MAX IEFFRE Y BY f W ATTORNEY p 26, 1950 M. L JEFFREY 2 23,310

ELECTROMAGNETIC LATCH TRIP SWITCH Filed Dec. 51, 1945 11 Sheets-Sheet e INVENTOR. MAX L JEFFREY ATTORNfY Sept. 26, 1950 M. L. JEFFREY v ELECTROMAGNETIC LATCH TRIP SWITCH Filed Dec. 31, 1945 ll Sheets-Sheet 7 J a a w] /0 k m1 W Sept. 26, 1950 M. L. JEFFREY 2,523,370

ELECTROMAGNETIC LATCH TRIP swI'rcH Filed Dec. I51, 1945 ll Sheets-Sheet 8 INVENTOR. MAX A. ffFF/Pf) ATTORNEY Sept. 26, 1950 k M. JEFFREY 2,523,370

ELECTROMAGNETIC LATCH TRIP SWITCH Filed Dec. 31, 1945 11 Sheets-Sheet 9 i i 5 '3, u g" I r I I I qr, I L w l l 7 INVENTOR.

/8O IB/OBY W ,4 TTOPNE Y Sept. 26, 1950 M. JEFFREY 2,523,370

ELECTROMAGNETIC LATCH TRIP SWITCH Filed Dec. 31, 1945 ll Sheets-Sheet 10 INVENIOR. MAX L. JEFF REY AUXILIARY ATTOR NEY Patented Sept. 26, 1950 UNITED STAT S PATENT OFFICE ELECTROMAGNETIC LATCH TRIP SWITCH Max L. Jeflrey, Shaker Heights, Ohio, assignor to The National Acme Company, Cleveland, Ohio, a corporation of Ohio Application December 31, 1945, Serial No. 638,554

9 Claims. (Cl. 200-406) This invention relates to improvements in switches, and more particularly to a quick acting multipole switch.

Although multipole switches have been contemplated heretofore, there have been certain disadvantages inherent in prior structures of which it is the purpose of the present invention to overcome. For instance, they have been rela tively cumbersome in structure as well as expensive to manufacture. lighten the structure weakened it and made the operation thereof unreliable.

By the present invention, I have provided a switch which is extremely compact and yet contains a number of features only to be found in larger and more complicated devices. The switch of my invention is characterized by its ability to quickly make and break a circuit, thus eliminating the tendency of contacts, carrying heavy current, to arc. Furthermore, the contact carrying structures are such that although the contacts are relatively close together, the tendency to are between contacts is reduced by increasing the path over which the arc would have to travel.

The invention also includes an improved snap a action mechanism which provides a quick make and break of the contacts. There is also contemplated a new type of thermally operated control which causes the switch to automatically open upon a power failure or in the presence of a sustained overload.

Still other advantages of the invention and the invention itself will become more apparent from the following description of an embodiment thereof, which description is illustrated by the accompanying drawings, and forms a part of this specification,

In the drawings:

Fig. 1 is a side elevational view on a reduced scale of the switch of my invention;

Fig. 2 is an end elevational view on an enlarged scale thereof;

Fig. 3 is a plan view of the switch of my invention with the cover removed;

Fig. 4 is a side view with the housing shown in section and the interior mechanism shown in elevation;

Furthermore, efforts to Fig. 5 is a side elevational view of the interior I Fig. 8 is a top plan view thereof;

Fig. 9 is a section taken from a plane indicated by the line 9-9 on Fig. 7, and looking in the direction of the arrows;

Fig. 10 is a fragmentary rear elevational view of a portion of the locking and release mechamsm;.

Fig. 11 is a fragmentary section taken on the line I i-l I of Fig. 10 and looking in the direction of the arrows;

Fig. 12 is an elevational view of a solenoid magnet used in my invention;

Figs. 13 and 14 are side elevational and to plan views respectively thereof;

Fig. 15 is a plan view of a fixed contact carrying block removed from the assembly;

Fig. 16 is a side elevational view, thereof;

Figs. 17 and 18 are similar views respectively of the other fixed contact carrying block;

Fig. 19 is a top plan view of a rotor removed from the assembly;

Fig. 20 is a side elevational view thereof;

Figs. 21 and 22 are opposite end views respectively thereof;

Fig. 23 is a bottom plan view of a pair of thermaliy controlled switches used in my invention;

Fig. 24 is a side elevational view thereof;

Fig. 25 is atop plan view of one of the switches removed from the supporting base;

Fig. 26 is an end view taken from a plane indicated by the line 2G26 of Fig. 28;

Fig. 27 is an end view of the opposite end;

Fig. 28 is a section taken on the line 28--2l of Fig. 25;

Fig. 29 is a side elevational view of the thermostatic element removed from the switch;

Fig, 30 is a plan view of the heater element removed from the assembly;

Fig. 31 is a plan view of the insulating element removed from the assembly;

Fig. 32 is an exploded view illustrating the manner of assembly;

Fig. 33 is an end elevational view of the support and actuating strip removed from the assembly;

Fig. 34 is the plan view of a control support removed from the assembly.

Fig. 35 is a plan view thereof;

Fig. 36 is a side elevational view of the support with the time control elements in place;

Figs. 37 and 38 are side and plan views respectively of one of the slide members used in the assembly;

Figs. 39 and 40 are similar views of the other slide element;

Figs. 41 and 42 are plan viewsof a pair of levers removed from the assembly;

Figs. 43 and 43a are side elevational views thereof;

Fig. 44 is an end elevational view of a fixed contact assembly removed from the switch;

Fig. 45 is a side elevational view thereof;

Fig. 46 is an end elevational view of. a movable contact member;

Fig. 47 is a side view thereof; and

Fig. 48 is a wiring diagram indicating one manner in which the apparatus may be used to control a circuit.

Briefly, the invention includes a housing having an operating shaft extending therethrough and which connects to a snap action mechanism. The snap action mechanism operates a movable contact carrying member which moves the movable contacts. into engagement with sets of fixed contacts.

The snap action mechanism has means connected thereto to release it from the operating position to open the contacts in event of power failure. The same release means is also operable by a thermally controlled overload switch to open the contacts in event of an overload.

Referring now to the drawings, throughout which like parts have been designated by like r eference characters.

The mechanism is provided with a housing which includes a base portion H], the upper portion 'of which is closed by a cover held on by screws 12 which extend through the cover and are threaded into bosses IS on the base housing. The end of the base housing is provided with a protruding boss 14 through which an operating 4 the rear side as viewed in Fig. 4 or the left as viewed in Fig. 6, and in the opposite side of the housing is a solenoid which operates in conjunction with the snap mechanism.

shaft l5 extends, the end of the shaft being serrated and carrying thereon the operating lever IS. The end of the lever is split, and a screw permits the lever to be securely clamped to the shaft in any desired position.

The side of the housing is provided with a plurality of threaded bosses |8 adapted to receive conduits, not shown, and through which wires may be conducted into the interior of the mechanism to provide the desired electrical connections.

As can best be seen in Fig. 4, the shaft l5 extends into the interior of the housing, being journalled in a bushing i9, and having a flanged head 20, the flange 2| of which is seated on a packing member 22 disposed in a cup 23 on they end oi the bushing I9. The outer end of the boss I! is provided with a counterbore 24 surrounding the bushing, and a helical spring 25 is seated in the end of the counterbore with the other end hearing against a flange 26 on the shaft IS. The flange 26 is secured to the shaft by a pin 21 (Fig. 3) which extends through the flange and shaft. The spring urges the shaft and lever outward securely seating the flange 2| on the packing 22 in fluid and gas sealing relation. The head 20 is provided with a transverse slot 28 (Fig. 3) adapted for engagement with a tongue 29 of an operating member hereinafter described.

The snap operating mechanism is disposed in the housing adjacent the end with the operating handle or to the right as viewed in Fig. 4. Back of the snap mechanism the fixed contacts supporting blocks extend longitudinally of the housing on opposite sides, and the rotor which carries ie movable contacts is disposed between the fixed blocks, being rotatably supported by its ends. A thermal overload mechanism is disposed in the lower portion of the housing on one side,

For a description of the snap operating mechanism reference will be had to Figs. '7 to 11, in elusive, wherein the mechanism is shown in detail, removed from its association with the other mechanisms.

As previously stated, the shaft II connects through the head" with the tongue 29. This tongue extends from the operating shaft 30 through the front of the snap mechanism support.

The snap mechanism is supported between a pair of vertical plates 3| and 32. The plate 3|, the formation of which is best shown in Fig. 7, is provided with a pair of rearwardly bent ears 33 adapted to be secured to bosses 34 integral with and disposed on opposite sides on the bottom of the housing by screws 35.

The rear plate is connected in spaced relation to the front plate by spacers 36 and 38' which are riveted into the rear plate and secured to the front plate by screws 31 which extend through the front plate and are threaded into the spacers.

The right end of the shaft 30 is provided with an enlarged head 4|! which carries the tongue 29. This head is rotatably journalled in an aperture in the plate 3| and is provided with a longitudinally extending slot 4| in which the end 42 of a spiral spring 43 is hooked, the spring encircling the shaft for approximately 3 convolutions and being hooked at 44 over the head of the screw 3'! which is enlarged for that purpose. The spring is tensioned to urge the shaft 30 in a clockwise direction as viewed in Fig. 'l. w

The rear end of the shaft 30 is provided with a reduced extension 45 adapted to be journal-led in the end of the rotor, the end of the rotor being journalled in the opening 45 in the plate 32, as will hereinafter more clearly appear, to provide a support for the end of the shaft 30.

The shaft 30 has secured therein at its mid portion by a, pin 49 a lever 50 which depends downward midway between the plates 3| and 32. The lever is provided with inwardly extending recesses on opposite sides which form a neck 5|. and the extremity is provided with portions 52 which extend laterally on opposite sides, the bottom faces of which are curved at 53 and 53' to provide cam surfaces.

Also carried by the shaft 30 is a second lever which is rotatably journalled on the shaft. The upper part of the lever has the same contour as the lever 50 and comprises two spaced parts 55 and 56 between which the lever 50 is disposed, as best shown in Fig. 9. The lower end of the lever is of generally square formation and supports a member 51 between the bottom ends which is riveted to the two parts and holds them in spaced parallel relation to each other. The lower surface of the member 51 is of generally arcuate formation and is provided with notch 58 extending transversely thereacross opposite the center of the lever. An opening extends through the notch toward the end of the lever 50 and a ball 60 is disposed therein.

The square portion 55 of the arm carries a housing 63 which is threaded into-the arm and protrudes through an elongated aperture in the plate 3|. This housing is provided with a bore in which is disposed a helical spring 64. The spring carries a head 65 engaging a ball 66 which is pressed into an opening 61 extending through the end of the lever 58. This acts as a detent which tends to hold the two levers in predetermined relation to each other; they can, however, attain relative movement, in which event the ball is pushed out of the detent formed by the opening 61 and rides on the surface of the lever 68.

The lever 58 is adapted to drive the lever 5556 through a C-shaped spring I8 of laminated construction. The spring surrounds the ends of the levers and arm with the free ends in engagement with the necked in portions 5I on opposite sides. It will, therefore, be seen that if the shaft 38 is rotated, the lever 58 is swung and that movement from the lever 58 is transmitted to the arm 55-56through the spring I8. If the lever 5556 meets with suflicient resistance, the ends of the spring are forced apart allowing the two levers to move relative to each other. If, however, the resistance against movement by the lever 5558 is overcome, the sprin III will cause this lever to swing quickly over into aligned relation with the other lever. This feature is utilized to cause the snap movement of the switch contacts. In carrying out this function, the arm 5556 is held during the major part of swing of the lever 58, the C-shaped spring having its ends forced apart, the arm and lever moving out of relative alignment until at a predetermined position the arm is released, and the C-shaped' spring snaps the arm into alignment with the lever. The arm being connected to the rotor carrying the movable contacts, a quick contact is made.

In carrying out this feature of the invention,

the lever 5556 is held against movement when the lever 50 is swung, by a catch, which catch is released by the cam surface on the lever after it has swung a predetermined amount. Supported between the plates 3| and 32 below the end of the lever 55-56 and to one side in the direction in which the lever is to swing is a block I2 which is provided with a square channel I3 ex tending through the block toward the axis of the lever. In the channel there is disposed a square plunger I4 which-is provided with a bore I5 in which a spring I6 is seated. The end of the channel I3 is closed by a strip I1 which is held in place by screws I8. The spring 1,-6 urges the plunger I4 upward into the notch 58, in which position it holds the lever 5556 against movement. The ball 68 rests on the end of the plunger 14.

When the lever 58 is swung counterclockwise as viewed in Fig. 'l, the lever 55-56 bein held against movement by the plunger 78, the two necks on the two levers move out of alignment against the pressure of the C-shaped spring I8. Continued rotation of the lever 58 swings the end 52 between the square portions until eventually the cam surface 53 on the lever 58 engages with the ball 68, pressing the ball downward against the plunger I4. The plunger I4 is forced downward by the ball and is eventually forced out of the notch 58. This releases the lever 55-56, and the C-spring I8 snaps the lever 55-56 over into alignment with the lever 58.

After the two levers are swung to the right, as just described, the lever 55-56 is engaged by the second plunger 88 where it is locked, until the lever 58 is swung back, at which time the plunger 88 is released by the other end 53' of the lever 58 in exactly the same manner.

The faces 52' on the lever 52 are adapted to engage, upon overtravel of the lever, with the bushings or spacers 36' which serve as stops therefor. In the position shown, the snap mech- 55-56 back to their normal open and 0113" positions. i As can best be seen in Fig. 11, the plunger 88 is provided with a. longitudinally extending slot 8| in the lower end of .which is disposed a pin 82. The pin extends transversely across the slot.

The rear end of the block I2 is formed with a vertically extending channel in alignment with the groove 8| and a lever is pivotally supported in the channel 84 on a pin 81. This lever is provided with a projection 86 which, when the lever is rotated, engages the pin 82 and forces the plunger 88 downward. The upper end of the lever ha a head 88 provided with a flat face 89 which is adapted to engage the bottom of the groove 8| and which serves as a stop to limit the inward movement of the lever, and hence the downward movement of the plunger. This lever is moved by the armature of a solenoid when a sustained overload occurs to cause the release previously described.

The solenoid is located in the lower right hand portion of the housing, as viewed in Fig. 6, and is shown in detail in Figs. 12 to 14, inclusive. It includes the E-shaped stator plates 9|, and the winding 92 into which the stem 83' ofthe armature 94 is adapted to extend. A pair of mounting brackets are provided at the upper end and each comprises an inverted U-shaped member 96 secured through the laminations by rivets 91, out turned ears 98 being provided on the upper end.

The head of the armature is provided with a recess in which a pin 99 is secured by a rivet I88. The pin has a head IM and a spring I82 which has one end bearing against the head and the other end against a plate I83 urges the armature to its outward or uppermost position as shown in the figures. The brackets 96 are secured to the plate 32 by screws I84, which extend through the brackets and are threaded into the plate. The other end of the solenoid is supported by a bracket I85, one end of which is secured to the strip I86 by bolts I81 that extend through the bracket and through the holes I88 in the end of the stator laminations.

In the operation of the solenoid, it is energized, by the circuit being controlled, to attract the armature into the winding against the pressure of the spring I82. In event ofpower failure, or as will hereinafter appear, in event of a sustained overload, the solenoid is de-energized and the spring I82 urges the armature outward. The head I8I engages the lever 88 which pulls the plunger 88 down out of the notch 58 releasing the lever 5556 and the spring 43 rotates the mechanism to the open position.

As previously stated, the rotor which carries the movable contacts and the blocks which carry the fixed contacts are disposed to the rear of the snap operating mechanism and extend longitudinally of the housing. A supporting plate I I8, similar in configuration to the plates 3| and 32, is provided and has rearwardiy bent ears III adapted to rest fill-821d be secured to bosses m at the bottom and end of the housing by screws 35. Extending between the rear plate IIO and the plate 32 which supports the back of the snap mechanism, on each side are strips I06. These strips hold the plates rigid and in properly spaced relation and provide means for supporting the fixed contact carrying blocks. a They may be se-' cured to the plates in any suitable manner, as by angle brackets III, Fig. 3, or by providing intumed flanges on the ends of the strips.

The fixed contact supporting members, as can best be seen from Fig. 6, are carried by the strips I on opposite sides of the housing, the one on the left side being disposed in a lower position than the one on the right and carrying contacm which face upward, while those on the right face downward.

The upper or right hand block is illustrated in Figs. 15 and 16, and the lower or left hand block in Figs. 17 and 18. The blocks are both formed of a suitable insulating material such as Bakelite," the upper or right hand block H being'of ing recess in the side of the block so the outer face of the strip and the side of the block lie flush with each other. The upper and inner portion of the block is provided with fixed contacts, the faces IIB of which face downward and which are provided with stems I I1 extending upard through the block and are secured by nuts I I8 to a terminal strip II9. Each terminal strip is provided with a connecting screw I20 threaded through the strip and into a bushing I2I embedded in the block.

As can best be seen in Figs. and 16, the material of the block extends upward between the strips and around the contact nut Ill to provide further insulation. The lower or left hand block is illustrated in Figs. 17 and 18 and is shown in cross section in Fig. 6. It is likewise secured to one of the strips I06 and carries the fixed contacts, the faces I20 of which face upward. These contacts are carried in projections I2I which extend inwardly from the inner side of the block. Likewise, they are provided with stems which extend through the block and are provided with connect ng nuts I22. Terminal strips I23 likewise connect the contacts to the terminal screws I24, which screws are threaded into bushings I25 that extend through the blocks, these being screwed on each end of the bushings whereby connection can conveniently be made to the top or bottom. It will also be noted that each of the blocks is provided with grooves between the contacts, those of the block I I5 being indicated at I26, and those of the left hand block at I25. It will be appreciated that the rranner of connection of the contacts is a matter of choice and will be governed largely by the specific application of the switch. This increases the electrical resistance path be tween the contact, and as will later appear, allow the ribs I21 of the rotor to extend therebetween, thus safeguarding against flash over between the contacts.

The rotor, which carries the movable contacts, is rotatably supported intermediate the fixed contact bloc", and adapted to be rotated to bring its contacts into engagement with the fixed contact". The r nruction o the rotor can bet be seen from Fig. 6, where it is shown in section,

andrlgs.l9to22,inclusive,whcreitlsshownremovcdfromtheassembly. 1

Asbestshowninl'ig.6,therotorh1clndua body of insulating material, such as Bahlitc. formed in two sections I33 which are cccurcd toge'therbyaboltIflthatcxtendsthroughthe The heads I32 of thebpltsaredlspacd inrecessesinoneofthesectionsandthccccuringnuts Ihsecurcdinrecessesintheother sccflon. Eachsectionisprovidedwithadnnncl I3lextendingacrostheabuttingsurfaccsand whichlineupontheoppositetomvide a passageway extending transverdy through the rotor. 1

A movable contact carrying strip I38 k dicposcdineachofthewaysbeim xovided with a central aperture I38 throughwhich the bolt I3I extends. The ends of cod: skip carry contacts I31 which face in opposite directlonsandtowardtherespcctivefixcdcontlcts with which they will ultimately E 8888- m the opposite side from each of the contads, helical springs I33 are provided, the ends of which are seatcdinrecesses Illandtheothermdsd which engage the strip and tilt it in a counterclockwise direction. The tilting of the strip is limited by inwardly extending homes I on the members I30. Intermediate each contact strip the rotor is provided with circumferentiaily extending'ribs I21, which ribs are adapted to extend into, but out of contact with, the grooves or channels I20 and Hi on the block carrying the fixed contact to thus provide a circuitous resistance path which, as previously menflmcd, serves to prevent flash over between the contacts upon the breaking of a circuitL' The ends of the rotor areprovided with trunnions I and I by which it is rotatably mpported in openings in the plates (and 32. The

trunnions are provided with stems Ill which are clampedinaxialopenlngsintheendofthe rotor by bolts or studs I. The trunnion I03 is provided with a projection I" which extends transverselyacrosstheaxisandisadaptcdto beengagedinaslotlllinthememberiiofthe snap mechanism (see Fig. 9) the projcctitn is also provided with an axial opening Ill adapted to receive the extension of the operating shaft 3!. The trunnion is thus supported in the opening 46 of the plate 32 and in turn provides abearing support for the shaft 30. It will be noted that the movable contacts are so disposed that they may be rotated into contact with the fixed contacts on the opposite blocks, and when so moved, establish a circuit from the contacts IIi through the strips Hi to the other contacts I20. As previously stated, thermally operated means is provided, which, in the presence of a sustained overload, causes the switch to be opened. Briefly, this includes a resistance or heater element serially disposed in the circuit being controlled and which, upon a predetermined value of current therethrough, heats a thermostatic element which moves the contacts to the open position. In the apparatus shown, there are two such devices, but since they are both the same, only one will be described. For a better understanding thereof, reference will be had to Figs. 23 to 28. inclusive. As best shown in Figs. 4 and 6, the fixed contact carrying block on the left side of thehousinghassecuredontheundcrsidea plate I52 which has suspended therefrom the thermostatic switches I53.

The switch is provided with a base plate Ill whichissecuredtotheplate "Unscrew: II.

9 The plate is provided with pairs of legs I56 and I51 at opposite ends, each pair of which supports blocks I58 and I59 respectively. Each of the blocks is provided with axially aligned cylindrical bores I60 and I6I into which the ends of the thermostatic element I62 extend. The bores -I60-I6I are sufficiently large to provide ample clearance space for the thermostatic element, and to permit the desired expansion thereof as hereinafter described, and yet serve as a guide and protector therefor.

At this point, for a better understanding of the invention, reference is made to Figs. 29 to 33, inclusive, which illustrate in detail the thermostatic element. Generally, it comprises an insulated heater element which is disposed between a pair of nested cylindrical pi-metallic elements. The outer bi-metallic cylinder is split longitudinally and is provided with outwardly and longitudinally extending lips along the split edge engage with and operate the switch.

More specifically, as can be seen in Figs. 29 and 33, the outer 'bi-metallic element is bent into the form of a cylinder I63 which is split at I64, being provided with a pair of downwardly extending flanges I65. A pair of guide pins I66 are provided on the upper end of the element opposite to the flanges I65, being adapted for guiding engagement with notches I61 in the plate 1 The heater element comprises a narrow strip of insulating material I68 which is preferably of mica, about which is wound the resistance wire I69. The ends of the wire are secured to metallic clips or bands I 10 as by spot welding. Lead wires I1I are also connected to each of the clips I10. One end of the mica strip is provided with three apertures for the reception of hollow rivets I12 which hold the assembly together as later described.

The heater element is sandwiched between wide strips of mica I13, Fig. 31, of which there may be six, three being disposed on each side of the strip as shown in Fig. 32.

The mica strips I68 and I13 and the heater element I6 are all secured together by the rivets I12 which are inserted through the outer aperturcs I14, after which the assembly is rolled into cylindrical form and inserted through the outer bi-metal element I63. A second bi-metallic element I63, Fig. 28, is inserted inside the rolled heater assembly, and a third rivet I15 is then inserted through the apertures I16 of the bi-metal element and through the center aperture of the heat assembly (I14) to rivet the entire assembly together. When so assembled, the resistance, or heater element, is held in alignment with and between the bi-metallic elements, and the wide strips of mica I13 extend beyond the ends providing ample protection against short circuits. t nd into guiding relation with the bores I60-I 6| of the blocks I58I59. The bimetallic elements are designed to expand when heated to open up the cylinder moving the flanges I65 apart, which movement effects the operation of the switch.

The flanges I65 are engaged by means, which is adjustable, and which resists the outward movement thereof and thus determines the length of time for which an overload must exist before the switch is opened as well as to afford a snap action therefor. The flanges also engage a pair of levers which open the switch contacts. I

As previously stated, the thermostatic element I63 is disposed with its ends in the bores of the These ends are also the ends that exblocks I58 and I59 and with the pins I66 being guided by the notches I61 in the plate I56. The wires "I of the heater element extend through notches I11 of the block I59 and are clamped therein by the clamp bar I18 which extends over the wires in the notches and is held in place by a screw I19 which is threaded into the block.

The means for controlling the time of operation of the switch and the operating levers, are supported on a block I80 which is secured to the lower ends of the blocks I58 and I59 by screws I8I. This block (I80) is best shown in Figs. 34 to 36, inclusive.

As can best be seen in Fig. 34, the block is formed with a channel I82 which extends transversely across the block and in which is disposed -a pair of slides (Figs. 37-38 and Figs. 39-40).

These slides are disposed in the channel, one on top of the other in nested relation. The slide,

Figs. 39-40, includes a fiat base portion I65 adapted to rest on the bottom of the channel, and one end of which is thickened at I86 to provide for lateral guiding engagement with the side of the channel. A pair of upwardly extending spaced tongues I81 are provided on the intermediate portion which provides a kerf therebetween, the tongues being adapted for engagement on opposite sides of one of the flanges I of the bi-metallic element. The remainder of the body at I88 is relatively thin and adapted to have seated thereon the other slide element (Figs. 37-38) which comprises a body portion I90, at one end of which is provideda pair of upwardly extending tongues I9I disposed in spaced relation to each other and adapted to engage on opposite sides the other flange I65 of the bimetalic elements. The slide I90 is adapted to seat on top of the thin portion I88 of the slide I in the channel I81, (see Figs. 35 and 36), and both slides are held in the channel by plates I93 that are secured to body I80 at the sides of the channel by screws I94.

When so secured in place, the tongues I81 and I9I extend above the channel at even height to each other and are in position to engage the spaced flanges I65 of the bi-metallic element.

Means is provided to hold the slides in position with the tongues I81I9I in properly spaced relation to each other and to restrict or resist the initial movement thereof by the bi-metallic element, in the form of a spring detent mechanism which engages notches in the sides of the slide. As best shown in Figs. 38 and 40, the slide I is provided with a notch I95 and the slides I85 with a notch I96. These two notches are so positioned that when the slides are in a predetermined position, one on top of the other, the notches are in vertical alignment with each other. The plate I80 is provided with a boss I91 which extends from the side of the channel I82 to the left, as viewed in Fig. 34, to the edge of the plate. This boss is provided with a bore or channel I98, the outer end of which is threaded, and a plunger I99 is disposed in the inner end of the bore, being provided with a rounded end 200. Theplunger is adapted to be pressed inwardly through the channel I82 with the rounded end 200 in simultaneous engagement with the notches I96-I 95, by a spring 20L One end of the spring 20I engages with the plunger and the other end with a screw 202 disposed in the threaded end or the bore. The pressure of the spring on the plunger is determined by the screw 202 which may be locked in adjusted position by the nut 203. I

It will therefore be seen that the slides must overcome the effect of the plunger to force it out of the notches I95-I9li before they can move longitudinally in the channel l82, and that -the pressure on the slides by a bi-metallic element, necessary to disengage them from the plunger, is dependent upon the adjustment of the screw 202. Therefore, when the bimetallic element is heated, the cylinder starts to open up. The opening movement is restrained until the pressure by the bi-metallic element upon the slides I90-I85 is sufficient to force the plunger out of the notches I95-I96. When this occurs, the resiliency of the bi-metallic elements snap the slides quickly to the limit of their movement in the outermost position. This thus provides a quick action for opening the contacts.

Inasmuch as the spring and detent mechanism restrain the movement of the slides, and the slides in turn restrain the movement of the bimetallic element, the movements of the .bimetallic elements are delayed, depending upon the pressure extended by the plunger in the slide notches. The time of operation may, therefore, be predetermined.

The flanges I65 engage between the ends of a pair of levers, which levers open the contacts. The base I80 is provided with a pin 205, disposed at the end of the base at the center line thereof, and upon which are disposed a pair of levers (Figs. 41-4311, inclusive). Each of the levers comprises a body portion 206, which is apertured at 201, to fit over the pin 205. The levers are each provided with an offset arm 208 from the end of which rises a flange engaging portion or pin 209. The other end of each lever is provided with an upwardly extending pin 2I5! adapted for engagement with the contact carrying members. The two levers are adapted to be pivotally disposed on the pin 205, one on top of each other, as best shown in Figs. 23 and 28. The pins 209 and 2I0 of one lever are longer than those of the other lever so that when they are disposed in assembled position, they rise to the same height. The flanges I65 of the bi-metallic element extend between the pins 209. The other end of each lever is provided with an upwardly extending pin 2I0 adapted for engagement with the contact carrying members. The two levers are adapted to be pivotally disposed on the pin 205, one on top of each other, as best shown in Figs. 23 and 28. The pins 209 and 2I0 of one lever are longer than those of the other lever so that when they are disposed in assembled position, they rise to the'same height. The flanges I65 of the bi-metallic element extend between the pins 209 and are adapted to move the ends outward upon expansion of the element, and since the two levers cross each other, the ends 2I0 are likewise moved outward, scissors fashion, to open the contacts.

The contacts are supported by the block I58, Fig. 28, which is provided with outwardly projecting portion 2I2 having three vertically extending slots. The center slot 2I3 receives therein the fixed contact assembly (Figs. 44 and 45) which comprises a pair of contact carrying strips 2I4 that are spot welded to a member 2I5 on opposite sides thereof and which extend downwardly and outwardly with the ends 2 I 6 in spaced parallel relation to each other and carrying the outwardly facing contacts 2H. The member 2I5 is provided with serrations 2I8 along the edge thereof. The center slot is somewhat wider than the others, and the contact assemb y is h d.

12 therein by a clamp bar 2I0 and screws 220 which extend through the clamp bar and are threaded into the portion 2 I2 of the block I58. The clamp bar engages with the serrations and securely holds the assembly in place. The member 2I5 is also provided with a solder lug 222 which extends outward from the edge of the member and adapted to receive connecting wires, not shown.

The outer movable contact members, illustrated in Figs. 46 and 47, included the support member 225, which, like the member 2I5, has a serrated edge. A single contact carrying strip 226 is secured to the side of the member. This strip is provided with a double U-shaped bend to provide flexibility thereto. the contact 221 being carried on the laterally extending end. Two of these members are provided and are each supported in the end slots, flanking the center contact, with the contacts 22'! in contact with the fixed contacts 2I'I. The ends of the strips 226 extend downward beyond the contacts at 228 and are disposed in engagement with the pins 2 I0, which, as previously stated, extend between these ends.

In operation, the heater element leads IH may be connected into the circuit being controlled. In event an overload occurs, th heating of the resistance element I69 heats the bi-metallic element causing it to expand and the flanges I65 to move outward. The movement of the flanges is restrained, however, by the slides I88 and I90 which cannot move until the plunger I99 is moved out of the detents I-I96. The continued expansion of the strip produces greater pressure on the slides, by which time the bi-metallic element has expanded to such an extent that when the slides are released, the bi-metallic elements spring to an open position snapping or quickly moving the slides to the limit of their movement. At the same time, the ends 209 of the levers 206 are quickly swung apart, which movement is transmitted to the end pins M0, and these in turn being in engagement with the ends 226, quickly disengage the contacts 221 and 2. The contacts remain in their open position until the bi-metallic element cools and returns to its normal position depicted in' the drawings and wherein the plunger again engages with the detents.

The plunger and detent mechanism also serve another purpose in that it holds the contacts closed and guards against accidental opening of the contact in event of shock or vibration.

It will be appreciated that the switch of my invention may be connected for controlling various types of apparatus in a variety of manners. The thermal overload sub-switch just described is preferably connected so that the-heater element is disposed in the load. The contacts which are opened by the operation of the bi-metalllc element are normally closed to complete a circuit to the solenoid in such a manner that when the main contacts are closed the solenoid is operated. In event any sustained overload is encountered after a predetermined time, which is determined by the adjustment of the plunger I99, the thermally operated switch is opened which de-energizes the solenoid and causes the main switch to be opened in the manner described.

One circuit which utilizes all of the elements of the mechanism is illustrated in Big. 48. In this figure there is shown a main source of power which, for instance, might be three phase alternating current 240 which may be connected to three of the fixed contacts M to I I60, inclusive, which are connected through the rotor and the movable contacts to the other fixed contacts Ina is also made from the load side of this line to the solenoid winding 92.

Terminal lb, which may be the center or common line, is connected directly to the center terminal M2 of the motor and a lead is also taken off of this wire for the operation of auxiliary" apparatus.

From the terminal I200 connection is made through the, other heater element I890 to the third terminal M3 of the motor.

The other two sets of terminals Hid-[20d and lite-Hue may connect directly to the auxiliary apparatus.

The solenoid winding connects to the outer contacts 221 of one of the thermal switches, thence through the center terminal 2|! to the outer terminals of the other thermal switch and through its center terminal by the line 24! to the auxiliary apparatus.

It will, therefore, be seen that the thermal switch is responsive to the load in motor circuit,

and that when this load is increased to open the thermal switch, the solenoid which is connected in the auxiliary circuit will operate to open the main circuit and also open the auxiliary circuit.

It will, therefore, be seen that I have provided an improved snap action structure which provides a smooth quick action and yet is extremely rugged and compact. The manner in which the rotor rotates between the stationary contact supports with the ribs extending into closely spaced relation to the grooves decreases the tendency for the same to are and burn the insulating material even though relatively heavy loads are being controlled. The switch will automatically open in event of power failure due to the deenergization of the solenoid and thus adds a safety factor highly desirable in many operations. The overload release characteristics are also highly desirable, particularly because it is adjustable to cause release after any predetermined time. Thus, overloads of short duration may occur, if desirable, without causing the switch to Op The thermal switch provides for a snap action which eliminates the tendency of the same to are.

It will be appreciated that the thermally responsive element, although shown and described as being particularly useful in operating the contacts which control an electrical circuit, is also useful in other devices than that shown and described. For instance, the element could be used to control the operation of valve means. Furthermore, although I have shown a heater element of the resistance type, it is quite within the purview of my invention to heat the bimetallic element by other means; for instance, the heat could be supplied to the interior of the element by a rod of conducting material, or it could be heated by directing a current of fluid through the cylinder. Furthermore, it could be heated by applying radio frequency currents thereto in a manner well known to those versed in the art. It will also be apparent that although only one pair of detents are shown for the slides which delay the operation of the bimetallic element, with this construction, additional detents can be provided on the slides which engage the elements when in the open position and hold the element against contraction until a predetermined amount of cooling takes place. Furthermore, although Ill the operating flanges apart upon heating of the element, it is quite within the purview of my invention to provide an element wherein the flanges tend to close together upon heating, by simply forming the element in the oppcflte directions; that is, with the higher expansible metal on the outside instead of the inside of the cylinder.

It will be appreciated that although I have shown only one resistanceelement for heating the bimetallic element, it is within the scope of my invention to employ more than one resistance element. That is, the bimetallic element could have a resistance element disposed on the outside as well as the inside, or in the structure shown, the bimetallic element could have another resistance element disposed inside of it. These resistance elements could be connected in separate circuits if desired to cause the operation of the switch upon overload in any one of the circuits.

Having thus described my invention, I am aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of my invention.

I claim:

1. An apparatus for use with a switch of the class described for controlling an electrical circuit having a pair of fixed members carrying fixed contacts and a rotor carrying movable contacts for circuit closing engagement with the fixed contacts, means for communicating a snap action to said rotor movable quickly from a normal position where the contacts are open to position where the contacts are closed, and operable to quiczly move the contacts from the closed to the open position comprising a first lever and a second lever and spring means connecting said levers, latch means for restraining movement of the second lever upon movement of the first lever from either position and means on the first lever to release said latch means upon a predetermined amount of relative movement therebetween, a solenoid connected into and energized by said circuit and means under control of said solenoid for holding said latch means in a state of release from said second lever when no power is flowing in said circuit and for causing said latch means to release said second lever from the closed contact position in event of power failure, and spring means connected to said rotary shaft to rotate sa d lever to switch open position upon release of said latch.

2. An apparatus for use with a switch mechanism having a plurality of stationary contacts and a rotor carrying movable contacts adapted upon rotation to move said movable contacts into engagement with the fixed contacts for controlling an electrical circuit, means for rotating said rotor quickly from contacts open position to contacts closed position or vic versa comprising rotary shaft, a first lever rigidly carried by said shaft and a second lever rotatably carried by said shaft and operatively connected to said rotor, spring means resiliently connecting said levers to each other, a first latch means for locking said second member against movement in a normal switch open position and means operable by said first lever upon relative movement of the first lever to release said latch means, said spring means adapted to rotate said second lever when released to a switch closed position, and a second latch means for locking said second lever in a switch closed position, said first lever adapted to release said second latch means upon a predetermined 15 relative movement between the first and second levers, and means including a solenoid disposed in said electrical circuit, adapted to release said secondlatchmeansandspringmeansconnected to said rotary shaft to rotate said levers to switch open position upon de-energization of said solenoid including a lever disposed for engagement with said latch means and a plunger on saidsolenoidandspringmeamforpresingsaidplunger against said lever.

3. An apparatus for use with a switch having spaced fixed contacts and a rotor having mov able contacts for movement into engagement with fixed contacts to control an electrical circuit including a snap mechanism for rotating said rotor with a quick make and break of said contacts comprisinga rotary shaft and a first lever rigidly carried thereby, a second lever rotatably journalled on said shaft and connected to said rotor, means to transmit swinging force from the first lever to the second lever comprising a spring disposed in engagement with said lever for holding them resiliently in a predetermined position relative to each other, latch means for holding said second lever against movement in a normal position wherein the switch contacts are open and in an operated position where the contacts are closed, said first lever adapted to be swung relative to said second lever to increase the tension on said spring meansv therebetween and adapted upon a predetermined relative movement therebetween to disengage said latch means and said spring means to rotate said second lever to close said contact upon disengagement of said latch means and said latch means adapted to lock said second lever in the contact engaged position, electrically operated means in said circuit operable upon closing said circuit to position said latch means for engagement with said second lever and operable upon failure of power in said circuit to release said latch means, and means connected to said rotary shaft to simultaneously rotate said levers back to a normal position and open said contacts upon release of said latch.

4. A snap action mechanism of the class described including a rotatable shaft, a first lever rigidly disposed on the shaft and swingable thereby, a second lever rotatably journalled on said shaft, spring means engaging said levers operatively connecting the first lever to the second lever, said second lever extending beyond the first lever and formed with a detent therein, locking means for engagement with said second lever ineluding a plunger and spring means for urging said plunger into said detent, said lever being formed with a passage opening into said detent and a movable member disposed in said passage, said first lever being provided with a laterally dispomd cam surface adapted upon relative movement between said levers to be swung into engagement with said movable member for moving said member against said plunger to disengage the plunger from said notch and release the second lever.

5. A snap action mechanism of the class described including a rotatable shaft, a first lever rigidly carried by said shaft, a second lever rotatably journalled on said shaft, spring means connecting the first lever to the second lever, said second lever extending beyond the first lever and provided with an arcuate end portion formed with a notch therein, locking means for engagement with said second lever including a plunger and spring means for urging said plunger into said notch, said' lever being formed with a passecond plunger likewise upon relative movement of the two levers.

6, A snap action mechanism adapted to convert a slow swinging movement to quick snap movement including a shaft adapted to be swung, a first lever rigidly carried by said shaft, a second lever rotatably carried by said shaft and having portions journalled on opposite sides of said first lever, a spring and detent carried by said second lever and engageable with the first lever to resist movement of the first lever relative to the second lever, first spring means connected to said levers for holding said levers in alignment with each other and resisting relative movement between the levers, said second lever having a portion disposed beyond and opposite to the end of the first lever, latch means for engagement with the second lever to hold it against swinging movement when the first lever is swung including a plunger disposed opposite the end of the second lever, said second lever being formed with a slot, second spring means engaging said plunger for holding said plunger in said slot, and means carried by the first lever to release said latch upon a predetermined swing of the first lever to permit said first spring means to swing said levers back into alignment comprising an opening formed in the second lever opposite said plunger and a ball disposed in said opening, said first lever being provided with a projection adapted upon a predetermined relative swing of the first lever to engage said ball to push said ball against said plunger out of said slot.

'1. A snap action mechanism including a first lever, means for swingably supporting said lever, a second lever rotatably carried by said means adapted for movement relative to the first lever, said levers being formed with necked-in seats spaced from the support means and spring means surrounding the supported ends of the lever and seated in said seats to hold said levers resiliently against relative movement to each other, said second lever having portions disposed on opposite sides of the first lever and said first lever being movable between said portions, said portions extending beyond the free end of the first lever and supporting a member opposite to and beyond the end of the first lever, said member being formed with a curved surface provided with a notch extending transversely thereacross in the midportion of said surface and with an opening toward the end of the first lever and through said notch, and ball means disposed in said opening, latch means for engagement with said second lever to hold it against movement in a normal position and a swung position comprising a block disposed beyond the end of said second lever and formed with spaced channels opening toward the axis of the support for said levers, plungers dispmed in said channels and spring means for urging said plungers toward said arcuate surface, said plungers adapted for alternate locking engagement with said notch in said second lever, said first lever being provided with laterally extending projections at its end, said .projections being formed with surfaces adapted upon relative swinging movement of the first lever to the second lever to engage said ball means and press said ball means downward into said notch to disengage the plunger engaged in said notch, said plungers when out of said notch adapted to ride on said arcuate surface.

8. A snap action mechanism including a first lever, means for swingably supporting said lever, a second lever rotatably carried by said means adapted for movement relative to the first lever, and spring means to hold said levers resiliently against relative movement to each other, said second lever having portions disposed on opposite sides of the first lever and said first lever being movable between said portions, said portions extending beyond the free end of the first lever and supporting a member opposite to and beyond the end of the first lever, said member being formed with a curved surface provided with a notch extending transversely thereacross in the midportion of said surface and with an aperture opening through said notch and toward the end of the first lever and ball means disposed in said aperture, latch means for engagement with said second lever to hold it against movement in a normal position and a swung position comprising a block disposed beyond the end of said second lever and formed with spaced channels opening toward the axis of the support for said levers, plungers disposed in said channels and spring means for urging said plungers toward said arcuate surface, said plungers adapted for alternate locking engagement with said notches in said secondle'ver, said first lever being provided with laterally extending projections at its end, said projections being formed with surfaces adapted upon relative swinging movement of the first lever to the second lever to engage said ball means and press said ball means downward into said notch to disengage the plunger engaged in said notch, said plungers when out of said notch adapted to ride on said arcuate surface and one of said plungers being provided with independent releasing means for releasing said plunger without relative movement between the levers.

9. A snap action mechanism including a first lever, means for swingably supporting said lever, a second lever rotatably carried by said means adapted for movement relative to the first lever, said lever being formed with necked-in seats 'spaced from the support and spring means sur- 5 rounding the supported ends of the lever and seated in said seats to hold said levers resiliently against relative movement to each other, said with said second lever to hold it against movement in a normal position and a swung position comprising a block disposed beyond .the end of said second lever and formed with spaced channels opening toward the axis of the support for said levers, plungers disposed in said channels and spring means for urging said plungers toward said arcuate surface, said plungers adapted for alternate locking engagement with said notches in said second lever, said first lever being provided with laterally extending projections at its end, said projections being formed with surfaces adapted upon relative swinging movement of the first lever to the second lever to engage said ball means and press said ball means downward into said notch to disengage the plunger engaged in said notch, said plungers when out of said notch adapted to ride on said arcuate surface and one of said plungers being provided with independent releasing means for releasing said plunger without independent relative movement between the levers and spring means for simultaneously swinging said levers back to normal position upon release of said plunger.

MAX L. JHFREY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,118,454 Weeks Nov. 24, 1914 1,532,212 Wilms Apr. 7, 1925 1,633,833 1 Townsend .June 28, 1921 1,710,191 Rowland Apr. 23, 1929 1,974,310 Lappin Sept. 18, 1934 2,199,638 Lee May "I, 1940 2,270,951 Jeffrey Jan. 27, 1942 2,326,299 Kingdon Aug. 10, 1943 FOREIGN PATENTS Number Country Date 217,867 Switzerland Nov. 15, 1941 391,323 Great Britain Apr. 27, 1933 

